After the dagger board repair i am more confident dealing with epoxy and fiberglass repairs but still a noob.
So boat has some minor (i guess) damage to the starboard hull. oh and it takes on water only in the starboard hull... so maybe they are related? I was thinking i would do a quick (and ugly) fix with some epoxy to fix the damage and maybe stop the leak (i doubt it).

so here is the area i am referring to.


Not a big area, only appears to be one layer of glass effected,



The area is right under the access hatch and under the tramp. From inside the hatch you can't tell where the damage is, you can feel it with your hand, but it's really hard to see. I couldn't tell you looking at the picture exactly where it is with any certainty. So i don't think this is the source of my water ingress.



Boat has been sitting outside on the beach (in VA) under a tarp with the hatches open for about a month. I was planning to just squirt some epoxy up into the slit, then trowel in some thickened epoxy, put some rare earth magnets on either side of the crack to keep it pressed down while it cures and then epoxy a thin layer over the top to fill any imperfections and holes, sand and that would be it. wasn't worried about gel coat or making it look good, the boat is old and area is basically hidden from view. But after doing more reading i'm now worried i could cause more damage if i trap water or moisture inside the hull, and that the epoxy alone isn't going to be a good barrier to moisture? - is this a problem for a beach cat that won't stay in the water? I'm not concerned about having a beautiful boat, but i am concerned about having a solid boat that I can sail and keep up for years to come.

Finally there is a second spot that i figured i'd just slap some more epoxy over to protect the glass



So am I asking for trouble not having had my hulls totally dried out for months and months? what is worse continuing to sail it with the damage and allowing more and more moisture in, or sealing it up and risking sealing some moisture in. It will be outside for VA winter.

I'd like to avoid having to grind and replace glass if i can help it, the boat is stored at the beach and I can't keep it at my home or fit it in my garage to do the work, so i'll have to do the work either on the beach or at best on a trailer. not the best place for serious repair work.

So then my final plan is with the epoxy that i have mixed up but don't use i'll spread some around the inside edge and bottoms of my dagger board case hoping to also seal up any tiny water leaks. is there a usual suspect for a Nacra 5.8 starboard hull leak that I could be looking for? I read a post about just spreading it all around the inside of the cases. i assume that only means the bottom where the case actually contacts the board and not the main body of the case? or am i wrong there? Also won't that cause a very tight fit for the boards? mine are already very snug. if i build it up at all i'm afraid i'll have to sand it all back off to get the board to fit.

Thanks,

--
1987 Nacra 5.8
1978 Isotope (sold)
--

In my opinion, if the glass is fractured (which it looks like from the 2nd picture), you're wasting your time just smearing epoxy in there. Damaged glass needs to be repaired with a fiberglass patch if you want to restore the original strength. Even if you're just looking to seal the damage, straight epoxy will eventually fail without any reinforcement.

We're not talking about a huge increase in time or difficulty by adding a patch, especially if you're not worried about cosmetics. Use some 60-80 grit sand paper to remove the gelcoat 1/2" to 1" all around the damage and then clean with acetone. Cut out two fiberglass patches (one slightly larger than the other) and laminate them over the damage using epoxy. After the epoxy cures, lightly sand the edges of the repair patch to blend in with the surrounding area. You can apply some thickened epoxy or Formula 27 over the patch if you want to fair it in even better and then shoot it with a little spray paint, or skip the F27 and just paint right over your patch.

The other thing to check, if this boat is sandwich construction (foam core), you need to make sure there is no delamination around the damaged area. You can do this very easily by tapping the edge of a coin all around the crack and listening for a dull sound. Dull sound = delamination and you would need to inject some epoxy in there to re-bond the skin to the core before applying the patch.

sm

That makes sense dogboy, guess i'll take my angle grinder and some sanding discs along with. The more i think about it the less i like just sealing it up. taking the gel coat off will also eliminate any residual moisture issues and i have the fiberglass mat.

I was really just hoping to avoid some work if there was no downside.

anyone have any suggestions on where to look for leaks? what are the usual suspects?

--
1987 Nacra 5.8
1978 Isotope (sold)
--

'87 is foam core. Suspect areas to look for a leak are the trailing edge of the dagger board trunk, and the drain plug. Great boat. She performs well in the ocean.

--
Philip
--

Quote

and the drain plug

+1
The N5.0 spent it's life on a beach. Continual sand exposure screwed the threads in the plug/housing. After replacing the housing/plug, we only drain those hulls a couple times all season. OK, we're lazy,but that cured 99% of water ingress.

--
Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
--

I've replaced the plugs/bulkheads with new ones and used 4200 to seal them in. i don't believe this is the source. (it was my first thought, but no such luck). So i'll focus on the dagger board case.

--
1987 Nacra 5.8
1978 Isotope (sold)
--

Rather than guessing at the source of the leak, why not just do a bubble test and actually find it?

Fill a spray bottle with soapy water. Jam a rubber hose in the drain plug opening. Blow about 10 or so lung-fulls of air into the hull and have someone walk around spraying the hull. Bubbles = leak.

sm



Edited by Dogboy on Sep 03, 2015 - 06:21 PM.

So I am new to this cat thing but I design and build cedar strip kayaks and may be able to help on this. I assume the damage you can see on the outside was due to an impact from the outside. That means the glass failure on the inside is probably much bigger than on the outside and from a structural standpoint needs repaired. Lucky for you that you have an access hatch and no one will every see if your glassing job is pretty on the inside. I would reach through the access hatch and scrub down (with detergent) the area for about 6 inches on either side of the damage to remove any contaminants or blush. Rinse that off and then sand the same area with 40-80 grit sandpaper to rough up the glass and smooth any edges. I would tape the outside of the crack to keep epoxy from running down the outside of the hull. I would then put down 2-3 layers of 6 oz-8 oz glass extending 6 inches to either side of the crack on the inside of the hull. I would probably wet the surface first with epoxy and put down one layer at a time making sure you wet it out each layer with epoxy but don't use so much epoxy that it floats. By the way smart phones work great for taking pictures in tight places to see how your job is going. Use a brush, squeegee, hand in a latex glove, what ever works to put down the glass as smooth as you can. It is best to start with a slightly wider piece of glass working to a smaller piece so the edge of a top layer does not go over the top of a lower layer. If the crack is long or in a place that it receives direct stress I may do 4 layers. Wait for a few hours until the epoxy is a little solid and remove the tape, with some luck the epoxy will have filled the crack with a smooth surface and a little work can make it a clean repair. Now you have a decision to make, glassing the outside is the best thing to do from a structure stand point, one layer of glass will likely do. I know people who do not glass and just paint over the epoxy to protect it and rely on the structure from the inside. That works for kayaks if I am way out of line on cats just let me know, public humiliation is not an issue with me. This should not take long, I had some serious cracks in the bottom fth hulls of the g cat I just got. Took about 90 minutes to repair both hulls (outside of the hulls), and another 90 minutes to fair the surface of the repair.

--
Scott Baxter
G CAt 5.7 about 20 sea kayaks and a sculling wherry
Salt Lake City Utah
--

I looked a little closer at your pictures I think if you went 3-4 inches to either side with the glass you would be good

--
Scott Baxter
G CAt 5.7 about 20 sea kayaks and a sculling wherry
Salt Lake City Utah
--

Scott,

The crack does not go through to the inside, and this is a foam core boat. I guess i could add some glass to the inside for piece of mind and just to be safe. That is why i was thinking a bit of epoxy on the outside to close up the crack in the gel coat and layer of glass. i think i'd close it right up it is very small, doesn't go through the boat and is between the cross bars, behind the boards and decently high up on the side that i don't think it's a high stress area. It sounds like your advice would work perfect if this was a solid glass boat, i'd totally go to town on the inside where no one could see the results of my mad scientist glass job!

But after reading Dogboys reply i think the best and smartest course of action will be to grind off the gel coat around the area and add some glass then seal it all up with some thickened epoxy. i probably won't bother with paint or gel coat at this time, its' under the tramp and will be protected from UV.

--
1987 Nacra 5.8
1978 Isotope (sold)
--

I missed the foam core aspect that changes things and significantly changes my assumption of damage to the inside fiberglass. I agree do the pressure check and based on the size and location I think a cosmetic fix may be best. If it works you have avoided some serious work, if it doesn't work I don't think you are risking much and you can just do the bigger repair.

--
Scott Baxter
G CAt 5.7 about 20 sea kayaks and a sculling wherry
Salt Lake City Utah
--

I repaired the damage from the outside, ground off the Gelcoat around the area, down below the actual cut and above the slight crease to expose all of the compromised glass. I used two pieces of fiberglass mat, used un-thickened epoxy to wet the entire area and the fiberglass, let it set up then went over the top with some epoxy with fairing filler, sanded it a bit to smooth it off. I feel good that the boat is sealed up again, the glass is reinforced and strong, and while it doesn't look perfect (and not perfectly smooth, I got tired of laying on my back under the tramp on the beach sanding), but i'm happy for a first time hull repair.

Feel a lot more confident now and know that the next one will come out a bit nicer.

I'm planning to build up the keel next year at some point, add some glass and leave a nice thick wear strip. At that point i will finish smoothing the repair i made and maybe add some paint just for looks.

Thanks to everyone for the feedback and help.

--
1987 Nacra 5.8
1978 Isotope (sold)
--